Adjustable front shocks on L300: Rancho RS9000XL series.
Posted: Thu Sep 13, 2018 8:47 pm
UPDATE: These are still too soft. Their firmest setting was ok for 5000km, but as they break in they get softer until they're as soft as the Pro-comps they replaced. Ugh.
I now recommend Bilstein 24-013369 (https://www.bilstein-shocks.co.uk/products/24-013369) shocks. Still a smooth drive, not harsh or sporty, but large bounces are nicely controlled.
TL;DR: Rancho part number RS999188 adjustable shocks fit L300 front suspension, but require a touch of modification to do so safely. On their hardest setting they aren't as hard as I expected, but still show a clear improvement in handling on the road. Softest is like driving a bouncy castle and will be good for off road. The Pro Comp shocks in my L300 were fine off road, but a bit too soft when towing the caravan. When they eventually shredded their lower bushes (as they do), I looked into adjustable shocks. Which, within my budget, means Rancho RS9000XL. There's nothing exactly right, but Rancho RS999188 (original fitment is for a 2000-2004 Nissan Xterra) will work with a couple of minor modifications.
First up, you'll need to press the lower sleeve out of the polyurethane bush, and replace it with the cross pin from your old shocks. File any sharp edges off the cross pin before pressing it in, and use grease to help it go in. Silicone grease is perfect for this application.
The Rancho shocks are slightly longer (when compressed) than I'm comfortable with (more on that later), so you want to drill out the hole in the lower mounting plate/washer so it fits over the nut on the pin. This gains us another 10mm of clearance.
The rubber boots that come with the shocks are too long and bunch up when the shock is fully compressed. Cut off about half of the boot and install it on the shock.
Install the shock as usual, with the adjuster facing inwards. It's easy to reach from underneath through the wishbone.
Now, these shocks don't have quite as much travel as the stock shocks. They have internal rebound bumpers so they shouldn't be damaged if a wheel comes off the ground (even on my suspension, which has 50mm spacers, the factory rebound buffer is almost fully compressed before the shock's internal bumper kicks in), but I wanted to be sure they wouldn't bottom out under compression because that's super bad. Here's how I checked that:
After removing the front wheels and putting the van on axle stands, I removed the torsion bar adjuster from the rear so the torsion bar wasn't under any tension, and disconnected one end of the sway bar so it wasn't restricting suspension movement either.
Then I removed the lower bump stop so I could see exactly how far the suspension could compress in a worst-case scenario (a split bump stop). Jacking up the suspension, I found that the suspension stops moving when the top ball joint binds, and the minimum distance from lower wishbone to lower shock mounting point was 235mm. The lower bump stop has a 2mm steel base and a 80mm bolt head welded to it (buried inside the rubber) which add up to 10mm- meaning that if the rubber were to completely fall off the bump stop, the maximum shock absorber compression would be 245mm.
The rancho shocks' minimum height (with the modified top mount)is 240mm. Excellent. First impressions: a setting of 5 (out of 9, with 9 being the firmest) feels very similar to my old Pro Comp shocks, your standard off-road comfort oriented shock absorber. A bit bouncy, but nothing catastrophic.
Setting 1 is like driving a blancmange. Not uncontrolled, but very, VERY soft. It would be lovely for a rocky offroad trail.
Setting 9 is fairly firm but not as much as I hoped. Nicely controlled body roll and much improved dive under braking, but if feels like a modern 4WDs suspension tuning (firm enough for confident high-speed road use) rather than harsh like a sports car. Maybe the big soft tyres are smoothing things out. I suspect I'll be leaving them on 9 for around town and freeway driving as well as for towing. We'll see.
I now recommend Bilstein 24-013369 (https://www.bilstein-shocks.co.uk/products/24-013369) shocks. Still a smooth drive, not harsh or sporty, but large bounces are nicely controlled.
TL;DR: Rancho part number RS999188 adjustable shocks fit L300 front suspension, but require a touch of modification to do so safely. On their hardest setting they aren't as hard as I expected, but still show a clear improvement in handling on the road. Softest is like driving a bouncy castle and will be good for off road. The Pro Comp shocks in my L300 were fine off road, but a bit too soft when towing the caravan. When they eventually shredded their lower bushes (as they do), I looked into adjustable shocks. Which, within my budget, means Rancho RS9000XL. There's nothing exactly right, but Rancho RS999188 (original fitment is for a 2000-2004 Nissan Xterra) will work with a couple of minor modifications.
First up, you'll need to press the lower sleeve out of the polyurethane bush, and replace it with the cross pin from your old shocks. File any sharp edges off the cross pin before pressing it in, and use grease to help it go in. Silicone grease is perfect for this application.
The Rancho shocks are slightly longer (when compressed) than I'm comfortable with (more on that later), so you want to drill out the hole in the lower mounting plate/washer so it fits over the nut on the pin. This gains us another 10mm of clearance.
The rubber boots that come with the shocks are too long and bunch up when the shock is fully compressed. Cut off about half of the boot and install it on the shock.
Install the shock as usual, with the adjuster facing inwards. It's easy to reach from underneath through the wishbone.
Now, these shocks don't have quite as much travel as the stock shocks. They have internal rebound bumpers so they shouldn't be damaged if a wheel comes off the ground (even on my suspension, which has 50mm spacers, the factory rebound buffer is almost fully compressed before the shock's internal bumper kicks in), but I wanted to be sure they wouldn't bottom out under compression because that's super bad. Here's how I checked that:
After removing the front wheels and putting the van on axle stands, I removed the torsion bar adjuster from the rear so the torsion bar wasn't under any tension, and disconnected one end of the sway bar so it wasn't restricting suspension movement either.
Then I removed the lower bump stop so I could see exactly how far the suspension could compress in a worst-case scenario (a split bump stop). Jacking up the suspension, I found that the suspension stops moving when the top ball joint binds, and the minimum distance from lower wishbone to lower shock mounting point was 235mm. The lower bump stop has a 2mm steel base and a 80mm bolt head welded to it (buried inside the rubber) which add up to 10mm- meaning that if the rubber were to completely fall off the bump stop, the maximum shock absorber compression would be 245mm.
The rancho shocks' minimum height (with the modified top mount)is 240mm. Excellent. First impressions: a setting of 5 (out of 9, with 9 being the firmest) feels very similar to my old Pro Comp shocks, your standard off-road comfort oriented shock absorber. A bit bouncy, but nothing catastrophic.
Setting 1 is like driving a blancmange. Not uncontrolled, but very, VERY soft. It would be lovely for a rocky offroad trail.
Setting 9 is fairly firm but not as much as I hoped. Nicely controlled body roll and much improved dive under braking, but if feels like a modern 4WDs suspension tuning (firm enough for confident high-speed road use) rather than harsh like a sports car. Maybe the big soft tyres are smoothing things out. I suspect I'll be leaving them on 9 for around town and freeway driving as well as for towing. We'll see.